Inflatable tourniquet cuff and method of making same

ABSTRACT

An inflatable tourniquet cuff includes an inflatable bladder having an outer layer with a predetermined thickness and an inner layer with a thickness that is less than the predetermined thickness of the outer layer. An opening in the bladder allows for the inflation and deflation of the bladder. A fastener system attached to the bladder releasably secures the bladder about a patient&#39;s limb so that the thin inner layer is positioned adjacent the patient&#39;s skin. The thin layer is relatively flexible in comparison to the thick outer layer and thus expands to a greater degree than the outer layer upon inflation of the bladder. A preferred method of manufacturing the cuff includes extruding two plastic ribbons of different thicknesses, forming openings at predetermined intervals along the thicker ribbon, pressing the ribbons together and sealing them along their side edges, cutting the combined ribbons into predetermined lengths, sealing the combined ribbons at their ends to form an inflatable bladder, hermetically sealing a hollow flange to the thicker ribbon in alignment with the opening, and attaching a fastener system to the bladder so that the bladder may be releasably secured about a patient&#39;s limb. Alternatively, the cuff may be extruded from a single plastic ribbon having both a thick wall and an opposing thin wall.

FIELD OF THE INVENTION

The present invention relates to medical tourniquets, and moreparticularly to disposable inflatable tourniquet cuffs that may bewrapped around a patient's limb and inflated to provide pressure forcontrolling blood flow in the limb.

BACKGROUND OF THE INVENTION

Inflatable tourniquet cuffs are commonly used in the medical industry.Due to the potential for soiling the tourniquet cuff during a medicalprocedure, tourniquet cuffs are often discarded as medical wastefollowing the procedure. This has led to the increased popularity ofdisposable inflatable tourniquet cuffs.

A typical disposable inflatable tourniquet cuff comprises an inflatablebladder contained within an outer covering. Due to the tendency of thebladder to balloon during inflation, a piece of stiffening material istypically placed between the outer covering and an outer side of thebladder opposite the patient's limb. The stiffening material preventsthe cuff from ballooning outwardly or obtaining a circular cross-sectionand possibly rolling or becoming twisted during use.

Two examples of disposable inflatable tourniquet cuffs that utilize astiffening member are U.S. Pat. No. 3,670,735 to Hazlewood, issued Jun.20, 1972, and U.S. Pat. No. 4,979,953 to Spence, issued Dec. 25, 1990.Similarly, in U.S. Pat. No. 5,201,758 to Glover, issued Apr. 13, 1993, aflexible covering is attached to a stiff backing plate and an inflatablebladder is positioned therebetween.

The prior art tourniquet cuffs noted above are relatively expensive duenot only to the cost of the stiffeners and the covering material, butalso to the relatively complex labor intensive process required toassemble these separate components into a tourniquet cuff. Furthermore,the stiffeners and the covering material only add to an alreadyoverwhelming amount of medical waste when they are disposed along withthe bladder at the conclusion of the medical treatment.

It is with regard to this background information that the improvementsavailable from the present invention have evolved.

SUMMARY OF THE INVENTION

One of the significant aspects of the present invention relates to aninflatable cuff that may be securely yet releasably fastened about apatient. Although the inflatable cuff may find use as a blood pressurecuff or a splint for immobilizing injured limbs, it is a particularobject of the present invention to provide a cuff that may be fastenedabout a patient's limb and inflated for use as a tourniquet.

The inflatable cuff includes an elongated inflatable bladder having anouter layer with a predetermined thickness and an inner layer with athickness that is less than the predetermined thickness of the outerlayer. A fastener system attached to the bladder releasably secures thebladder about a patient's limb so that the thin inner layer ispositioned adjacent the patient's skin. Upon inflation of the bladder,the gas pressure within the bladder expands the relatively flexible thinlayer to a greater degree than the thick outer layer, thereby preventingthe bladder from ballooning and assuming a circular cross-section.

One preferred embodiment of the inflatable cuff includes two plasticsheets of differing thicknesses sealed together along their edges toform the inflatable bladder. Prior to sealing the two sheets, an openingis formed in the thicker sheet so that a hollow flange adapted to beconnected to an inflation source may be hermetically sealed to thethicker sheet in line with the opening. The fastener system ispreferably attached to the thicker sheet following the formation of thebladder. The fastener system allows the bladder to be wrapped about apatient's limb so that the thin sheet contacts the limb. When the cuffis used as a tourniquet, an inflation source connected to the flangeinflates the bladder to a pressure sufficient to reduce the flow ofblood within the patient's limb. The two sheets are preferably extrudedfrom a transparent plastic so that medical personnel may view theportion of the patient's limb covered by the inflatable cuff. However,when the benefits of a transparent bladder are not required, an opaqueplastic may be used to form the bladder. Additionally, a flexiblepadding material may be affixed to the thin sheet so that the paddingcontacts the patient's skin once the cuff is wrapped around thepatient's limb.

Another significant aspect of the present invention relates to a methodof manufacturing the inflatable cuff. The method includes extruding twoseparate plastic ribbons, one ribbon having a greater thickness than theother. Openings are then formed at predetermined intervals along thethicker ribbon. The thick and thin ribbons are then pressed together andsealed along their side edges. The combined ribbons are subsequently cutinto predetermined lengths and sealed at their ends to form aninflatable bladder. The hollow flange is then hermetically sealed to thebladder in line with the opening and the fastener system is attached tothe bladder so that the bladder may be releasably secured about apatient's limb.

Alternatively, the bladder may be extruded from a single plastic sheethaving a thick wall and an opposing thin wall. The plastic sheet is cutinto predetermined lengths and an opening is formed in the thick wallprior to sealing the ends of the bladder. The hollow flange and thefastener system are then attached to the bladder and, regardless ofwhether the plastic bladder is transparent or opaque, a flexible paddingmay be attached to the thin wall to enhance the comfort of theinflatable cuff.

A further significant aspect of the inflatable cuff of the presentinvention is the relatively small number of parts which togetherconstitute the cuff. The lack of extraneous components such as an outercovering or a separate stiffening member substantially reduces the costof the cuff and reduces the waste associated with the disposal of thecuff. Furthermore, the relatively simple manufacturing process furtherreduces the cost of the cuff, thereby enhancing the disposable nature ofthe cuff.

A more complete appreciation of the present invention and its scope canbe obtained from understanding the accompanying drawing, which isbriefly summarized below, the following detailed description ofpresently preferred embodiments of the invention, and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a tourniquet cuff embodying the presentinvention.

FIG. 2 is an isometric view illustrating the tourniquet cuff shown inFIG. 1 wrapped about a patient's limb (shown in phantom) and connectedto a pump and a pump monitor.

FIG. 3 is a section taken substantially in the plane of line 3--3 onFIG. 2.

FIG. 4 is an enlarged section taken substantially in the plane of line4--4 on FIG. 1.

FIG. 5 is an enlarged section taken substantially in the plane of line5--5 on FIG. 1.

FIG. 6 is an enlarged partial section taken substantially in the planeof line 6--6 on FIG. 1.

FIG. 7 is an enlarged partial section taken substantially in the planeof line 7--7 on FIG. 1.

FIG. 8 is an isometric view of a first alternative embodiment of thetourniquet cuff of the present invention.

FIG. 9 is an enlarged partial section taken substantially in the planeof line 9--9 on FIG. 8.

FIG. 10 is an isometric view of a second alternative embodiment of thetourniquet cuff of the present invention.

FIG. 11 is an enlarged section taken substantially in the plane of line11--11 on FIG. 10.

FIG. 12 is an exploded isometric view of the components of thetourniquet cuff shown in FIGS. 1 and 2, with two sheets of an inflatablebladder shown partially delaminated for clarity.

FIG. 13 is a schematic view of a manufacturing sequence illustrating theassembly of the tourniquet cuff shown in FIGS. 1 and 2.

FIG. 14 is a schematic view of an alternate manufacturing sequence forthe tourniquet cuff of the present invention.

FIG. 15 is an enlarged section taken substantially in the plane of line15--15 on FIG. 14.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a disposable inflatable tourniquet cuff 20 embodying thepresent invention. FIG. 2 illustrates the tourniquet cuff 20 wrappedaround a patient's limb 22. A single gas line on the tourniquet cuff 20is connected to a valve 26 which, in turn, is connected by separatetubes 28 to an inflation source 30 and a gas pressure gauge 32. Theinflation source 30 may comprise a conventional hand-operated air pumpas shown in FIG. 2, or it may comprise an automatic tourniquet monitorthat includes an air compressor. The valve 26 and gauge 32 allow medicalpersonnel to monitor the gas pressure within the tourniquet cuff 20 in aconventional manner as the cuff is inflated.

As shown best in FIGS. 3-7 and 12, the tourniquet cuff 20 is preferablyformed from a thick outer sheet or layer 34 of vinyl plastichermetically attached to a relatively thin inner sheet or layer 36 ofvinyl plastic to form an inflatable bladder 38. The outer and innersheets 34 and 36, respectively, are preferably rectangular in shape andare hermetically sealed together along a peripheral area extendingaround the respective side edges 40 and 42 of the sheets 34 and 36. Theseal 44 between the outer and inner sheets 34 and 36 is conventional andpreferably comprises a heat seal formed by applying a hot air jet to theedges of one of the sheets and then pressing the two sheets together.Alternatively, an ultrasonic welder may be used to heat seal the sheets34 and 36 along their edges 40 and 42. Instead of a heat seal, the seal44 may be formed by an adhesive applied around the edge of one of thesheets prior to pressing the two sheets 34 and 36 together. In place ofthe adhesive, a solvent may be used to partially dissolve the vinylalong the edges 40 and 42 of both sheets 34 and 36 so that the seal 44forms along their peripheral area as the sheets are pressed together andthe vinyl is re-formed.

An opening 45 is provided through the thick outer sheet 34 adjacent oneend of the sheet. A hollow flange 46 having a flat first end 50 and anL-shaped neck 51 is hermetically sealed in a conventional manner to anouter surface 52 of the thick outer sheet 34 in alignment with theopening 45. Alternatively, the flat first end 50 may be sealed to aninner surface 54 of the thick outer sheet 34, prior to attaching theouter and inner sheets 34 and 36 together, so that the L-shaped neck 51of the flange 46 extends through the opening 45. The seal between theflange 46 and the outer sheet 34 prevents gas from escaping through theopening 45 around the flange 46, thereby maintaining the integrity ofthe bladder 38. A first end 58 of a flexible hose 60 is hermeticallysealed within the neck 51 of the flange 46, while a coupling piece 62 isattached to a second end 64 of the hose 60. The coupling piece 62 may beattached to any conventional inflation system, which might include thevalve 26 shown in FIG. 2, to provide for inflation and deflation of thebladder 38.

The bladder 38 has a length dimension sufficient to extend completelyaround a person's limb 22. A fabric strap 66 with a length dimensionthat is shorter than the length of the bladder 38 is attached to thethick outer sheet 34 by conventional means (such as an adhesive or anultrasonic weld) and extends from a first end 68 of the bladder 38toward a second end 70, as shown in FIG. 1. The fabric strap 66 containsa multiplicity of fabric hooks 72 which face away from the thick outersheet 34. A fabric tongue 74 having a multiplicity of fabric loops 76along a portion of its length is attached in a conventional manner tothe thick outer sheet 34 adjacent the second end 70 of the bladder 38 inlongitudinal alignment with the strap 66 so that the fabric loops 76face in an opposite direction from the fabric hooks 72. The fabrictongue 74 extends beyond the second end 70 of the bladder 38 so that itsfabric loops 76 may releasably engage the fabric hooks 72 on the fabricstrap 66 when the tourniquet cuff 20 is wrapped about a patient's limb22 with the thin inner sheet 36 contacting the limb. The lockingengagement of the fabric loops 76 and hooks 72 holds the tourniquet cuff20 in position about the limb 22.

The opening 45 and the flange 46 are preferably positioned adjacent thesecond end 70 of the bladder 38 as shown in FIGS. 1, 2 and 12. Thefabric tongue 74 preferably includes an opening 78 of sufficient size tofit over the L-shaped neck 51 of the flange 46 prior to the attachmentof the hose 60 (FIG. 12). Anchoring the fabric tongue 74 about theflange 46 as shown in FIGS. 1, 2, 5 and 12 reduces the potential foraccidentally pulling the fabric tongue 74 off the outer sheet 34 whiletightening the tourniquet cuff 20 about a patient's limb 22.

The difference in thickness between the outer and inner sheets 34 and 36provides the thin inner sheet 36 with a higher degree of flexibilitythan the thick outer sheet 34. Thus, upon inflation of the bladder 38,the relatively flexible thin inner sheet 36 expands toward and conformsto the patient's limb 22. With reference to FIG. 3, inflation of thebladder 38 causes only a slight outward expansion of the thick outersheet 34, while the more flexible thin inner sheet 36 is expanded to agreater degree. In this manner, the thick outer sheet 34 prevents thebladder 38 from ballooning and assuming a circular cross-section whichwould be undesirable due to the tendency of a circular bladder to rollor become twisted.

While various thickness ratios would be suitable for the outer and innersheets 34 and 36, the preferred embodiment of the tourniquet cuff 20utilizes vinyl plastic extrusions wherein the outer sheet 34 isapproximately four times thicker than the inner sheet 36. Specifically,the preferred embodiment utilizes an outer vinyl plastic sheet 34 and aninner vinyl plastic sheet 36 that are approximately 0.08 and 0.02 inchesthick, respectively. In this manner, the inner sheet 36 is relativelyelastic in comparison to the outer sheet 34 and may return to its normalsize once the bladder 38 is deflated. Thus, despite the disposablenature of the cuff 20, the preferred vinyl plastic bladder 38 may allowfor repeated inflation and deflation cycles.

Additionally, the outer and inner sheets 34 and 36 are preferably formedfrom a transparent material to allow medical personnel to view theportion of the patient's limb 22 covered by the bladder 38. An opaquerather than a transparent material may be used when the benefits of atransparent bladder are not required. While the preferred embodiment ofthe present invention utilizes medical grade vinyl plastic sheets, thoseskilled in the art will undoubtedly discern other materials that may besubstituted for the vinyl plastic. However, due to discomfort that mayresult from pressing vinyl plastic or a similar material against apatient's skin, the tourniquet cuff 20 of the present invention mayinclude a flexible foam padding 80 attached to the thin inner sheet 36in a conventional manner. Thus, as shown in FIG. 3, only this relativelycomfortable flexible padding 80 contacts the patient's skin once thetourniquet cuff 20 is wrapped around the patient's limb 22. However, ifthe foam padding 80 is not transparent it will impede or eliminate theability to view the patient's limb 22 through the preferably transparentbladder 38 of the tourniquet cuff 20.

FIG. 13 illustrates the preferred method of manufacturing and assemblingthe tourniquet cuff 20 of the present invention. First, two separateextruders 82 form continuous vinyl plastic ribbons 84 and 86 ofdifferent thicknesses to form the respective outer and inner sheets 34and 36. Next, a hole punch 88 preferably forms the openings 45 atpredetermined intervals along the thicker ribbon 84. The thicker ribbon84 is then transported by roller wheels 90 (only one of which is seen)which direct the thicker ribbon 84 toward the thinner ribbon 86. Priorto the merger of the two ribbons 84 and 86, a pair of transverselyspaced nozzles 92 (only one of which is seen) preferably apply hot airjets to the side edges 42 of the thinner ribbon 86. The sides of the tworibbons 84 and 86 are then pressed together by opposing press wheels 94to thermally seal the ribbons along their edges 40 and 42. Although hotair jets are preferably used to form the thermal seal, an ultrasonicwelder may be used in place of the nozzles 92 to heat seal the tworibbons along their side edges as they are pressed together.Alternatively, a solvent or an adhesive may be applied to the edges ofone of the two ribbons prior to pressing the two ribbons together.

Once the side edges of the two ribbons are sealed, a shearing machine 96preferably cuts the combination into predetermined lengths, and the endsof the two ribbons are sealed to one another to complete the formationof the bladder 38. As shown in FIG. 13, ultrasonic welders 98 arepreferably used to seal the ends 68 and 70 of the bladder 38.

Flanges 46 are then sealed to the outer surface 52 of the outer sheet 34above and in alignment with the opening 45 (FIG. 12) in a conventionalmanner such as through ultrasonic welding or the application of asolvent. Next, the fabric strap 66 and tongue 74 are attached to theouter sheet 34 (FIG. 12), while the flexible padding 80 (if desired) isattached to the inner sheet 36. Finally, the hose 60 (FIG. 12) ishermetically sealed within the neck 51 of the flange 46 to complete theassembly of the tourniquet cuff 20.

FIG. 14 illustrates an alternative method of forming the bladder 38wherein a single extruder 100 forms a vinyl plastic ribbon 102 having athick wall 104 and a parallel opposing thin wall 106 (FIG. 15). Theshearing machine 96 cuts the ribbon 102 into predetermined lengths, anda hole punch 108 then inserts an arm or mandrel (not shown) between thetwo walls 104 and 106 and conventionally forms the opening 45 in thethick wall 104. The ultrasonic welders 98 then seal the ends of thelength of ribbon 102 to complete the formation of the bladder 38. Theflange 46, fabric strap 66, fabric tongue 74 and flexible padding 80 arethen attached to the bladder 38 (FIG. 12), as described above. Thebladder formed in accordance with the method of FIG. 14 differs from thebladder formed in accordance with the method of FIG. 13 only in that theedges of the thick and thin walls are integrally connected (FIG. 15)rather than being hermetically connected.

A first alternative embodiment 120 of the tourniquet cuff is shown inFIGS. 8 and 9. The cuff 120 is substantially similar to the cuff 20shown in FIGS. 1 and 2, with like reference numerals used to denote likeparts such as the bladder 38. However, the cuff 120 further includes asecond opening (not shown) formed in the thick outer sheet 34 and asecond flange 122 hermetically sealed within the opening in fluidcommunication with the bladder 38 (FIG. 9). The second flange 122 is inlongitudinal alignment with the first flange 46 to further anchor thefabric tongue 74 to the thick outer sheet 34. A second flexible hose 124mated to the second flange 122 includes a second coupling piece 125adapted for connection to a pressure gauge (not shown) which willmonitor the actual flow-through gas pressure within the bladder 38 andact as a backup to the pressure gauge 32 shown in FIG. 2.

A second alternative embodiment 126 of the tourniquet cuff is shown inFIGS. 10 and 11. The cuff 126 includes the same outer and inner sheets34 and 36 used in the first two embodiments 20 and 120 described above.However, the cuff 126 includes an additional longitudinal seal 128between the outer and inner sheets 34 and 36 along a longitudinalcenterline of the sheets to form two separate, relatively narrowinflatable bladders 130 and 130'. Like reference numbers are used todenote like parts on the tourniquet cuff 126, while a prime (') suffixis used to differentiate between the two bladders 130 and 130'. Thebladders 130 and 130' each contain the single flange 46 and 46' andconnecting hose 60 and 60', respectively similar to the arrangement ofthe tourniquet cuff 20 shown in FIGS. 1 and 2. However, both hoses 60and 60' are connected to a single adjustable valve 132 (FIG. 10) whichis capable of selectively establishing pump communication with eitherbladder 130 or 130', or with both bladders simultaneously. Such a dualbladder design allows medical personnel to initially inflate one of thebladders and then switch to the other bladder when the pressure exertedby the first bladder becomes irritating or painful for the patient. Thisprocedure, known as a Bier block, is particularly useful in regionalantiseptic procedures where the patient remains fully conscious.

The method of forming the tourniquet cuff 126 shown in FIGS. 10 and 11is identical to that described above (FIG. 13) with respect to the cuff20 shown in FIG. 1, except that the additional longitudinal seal 128 isformed along the longitudinal centerlines of the ribbons 84 and 86 (FIG.11) at the same time the ribbons are sealed along their side edges 40and 42. Alternatively, the bladders 130 and 130' of the cuff 126 couldbe formed by a single extrusion, similar to that shown in FIG. 14.

The disposable tourniquet cuffs of the present invention have severaladvantages over prior art disposable tourniquet cuffs. By utilizingouter and inner sheets or walls of different thicknesses, no additionalstiffening member is required to control the ballooning tendency of thebladder. Additionally, no extra outer covering is required to maintainthe relative positions of the bladder and the stiffening member. Theomission of these extra components represents a substantial savings inboth the material and the manufacturing costs involved in assembling thedisposable tourniquet cuff. Additionally, the reduced number ofcomponents represents a reduction in medical waste over the prior artdisposable cuffs.

Three presently preferred embodiments of the present invention have beendescribed with a degree of particularity. These descriptions have beenmade by way of preferred example and are based on a presentunderstanding of knowledge available regarding the invention. It shouldbe understood, however, that the scope of the present invention isdefined by the following claims, and not necessarily by the DetailedDescription of the Preferred Embodiments.

The invention claimed is:
 1. An inflatable tourniquet cuff comprising:anouter sheet having a predetermined thickness; an inner sheet attached tosaid outer sheet to form a first sealed bladder and a second sealedbladder between said outer and inner sheets, said first sealed bladderextending adjacent said second sealed bladder and said inner sheethaving a thickness that is less than the thickness of said outer sheet;said first sealed bladder including a first opening through which gasmay flow to inflate and deflate said first sealed bladder separatelyfrom said second sealed bladder; said second sealed bladder including asecond opening through which gas may flow to inflate and deflate saidsecond sealed bladder separately from said first sealed bladder; andmeans for releasably securing the first and second bladders about apatient's limb so that the inner sheet is positioned adjacent to thepatient's limb.
 2. An inflatable tourniquet cuff as defined in claim 1,further including a flexible pad attached to the inner sheet so that thepad contacts the patient when the first and second bladders are securedabout the patient's limb.
 3. An inflatable tourniquet cuff as defined inclaim 1, wherein said outer and inner sheets are formed as a singleplastic extrusion.
 4. An inflatable tourniquet cuff as defined in claim1, further including:a first connecting hose sealed within said firstopening in fluid communication with said first bladder, said firstconnecting hose adapted to be connected to an inflation source forinflating and deflating said first bladder; and a second connecting hosesealed within said second opening in fluid communication with saidsecond bladder, said second connecting hose adapted to be connected toan inflation source for inflating and deflating said second bladder.